Percussion attachments for rotary drills



April 18, 1961 J E. NINDEL 7 PERCUSSION ATTACHMENTS FOR ROTARY DRILLS Filed Aug. 15, 1958 emu 23 ,22 ,23 '9- FT /24 I t M I. I

INVENTOR. John E. Nindel United I States Patent PERCUSSION ATTACHMENTS FOR ROTARY John Nindel, Latrobe, Pa.

Filed Aug. 15, 1958, Ser. No. 755,316 5 Claims. cue-22) The invention relates to percussion attachments for portable rotary drills and the like and particularly to a simple device adapted to convert rotary motion of a portable drill shaft into percussion blows to the shank of the drill.

There has long been a need for a simple device capable of converting the rotary motion of the shaft of. a portable drill into controlled, successive impact blows applied to the shank of the drill while the drill is simultaneously rotated.

Many expedients have been proposed to accomplish this purpose. Most of the devices heretofore proposed have incorporated a complex spring mechanism for imparting the percussion action, for example, Beeson Patent No. 2,794,621. Other proposals have been made incorporating complex holding and sleeve attachments as, for example, Lundquist Patent No. 2,724,573. The present invention eliminates these complex sleeve holding and spring driving mechanisms and provides a simple unitary construction on the housing of the drill itself.

In a preferred embodiment of my invention, I provide in a percussion attachment for rotary drills having a housing in which is journaled a driving shaft, a fixed element for attachment on the housing and surrounding the driving shaft, a sleeve on said driving shaft rotatable therewith, a driven element mounted on said sleeve coaxial therewith for rotation therewith and for limited axial movement thereon, cam means on one of said fixed elements and said driven element and mating cam follower means on the other of said fixed element and said driven element. Preferably, drill holding means is provided on the driven element such as a Jacobs chuck or the like. V

In the foregoing general description, I have set out certain objects, purposes and advantages of my invention. However, other objects, purposes and advantages will be apparent from the following description of certain preferred embodiments and in the accompanying drawings wherein I Figure 1 is a side elevation of the percussion attachment of my invention mounted on a portable drill;

2,979,962 Patented Apr. 18, 19561 2 of housing 10. A retaining ring 18 slidably fits over the cam ring 17 and is held on the end of housing 10 by set screws 19. The retaining ring 18 is provided with lock pins 20 which fit into holes 21 in the cam plate 17 to hold the plate immovably on housing 10. An annular cylindrical member13 is mounted on stub shaft 12 and is held in position for-rotation therewith by a set screw '14theend of which fits. in keyway 15 on the stub shaft 12. The cylindrical member 13 is adapted to move axially on stub shaft 12 with a set screw 14slid ing in keyway 15 and settingthe limits of axial movement. The annular member 13 is provided with a threaded opening 22 to receive a. conventional chuck 23 and dr -When theshaft 511 of the drill is rotated stub shaft12 is rotated therewith. This causes the cam follower sur-' face 16 on the annular member 13 to ride up and down on the cam surface 25 of cam plate 17 thereby causing the annular member 13 to reciprocate as well as rotate,

with the stub shaft 12. This in turn rotates the chuck 23 and drill 24 while at the same time imparting reciprocating motion from right to left and vice versa viewing Figure 1. A pin 26 having a tapered point 27 is provided in a threaded opening 28 nearthe end of annular member 13 so that the tapered end 27 may be brought to bear against the end of the shaft 12. This may be used to limit the length of the stroke of member 13 by limiting the extent of movement to the left viewing Fig-.

ures 1 and 2. Alternatively, the stroke of member 13 may be limited by positioning the threaded end 23a of the chuck 23 in opening 22. This feature of limiting the extent of stroke coupled with a single cam surface 16 on the annular driven member 13 is important for I have found that the length. of stroke and sharpness of impact are important in drilling various materials, and this structure provides a means for controlling the length of stroke and thereby the position at which the cam follower contacts the cam means which in turn affects the sharpness of the percussive blow.

In Figures 4, 5 and 6, I have illustrated a second embodiment. In this embodiment a stub shaft 40 is provided identical with the stub shaft 12 of Figure 1. A cam plate 41 surrounds the rear end of the stub shaft 40 in the manner of cam plate 17. Cam plate 41 is surface thereof forming a cam follower. The cam plate Figure 2 is a vertical section through the attachment I,

shown in Figure l;

Figure 3 is an isometric exploded view of the fixed element and the driven element of Figures 1 and 2;

provided with a drive shaft 10a internally threaded to,

receive a chuck. A stub shaft 12 having a cylindrical body 12a and a threaded portion 12b is inserted into the threaded end of shaft 11. A cam plate 17 surrounds the the driven element of rearend of the stub shaft 12 and bears against the end 41 is fixed to the housing of the drill by a retaining ring 43 in identical fashion with cam plate 17 and retaining ring 18. An annular cylindricalmember 44 is slidably mounted on stub shaft 40 in the same manner as member 13 and is provided with a set screw 45 operating in key way 46 as in the case of Figure 1. The annular member 44 is provided with spaced recesses 47- in line with the 1 and 2. Again thelength of stroke may be controlled v by a threaded pin 49 or by positioning the threaded shaft of the chuck as described in Figures 1 and 2.

While I have illustrated and described certain pre'ferred embodiments of my invention, itwill' be understood that this invention may be otherwise embodied within the V scope of the following claims.

I'clairn: 1. A percussion attachment for rotary drills having a housing and a rotatable drive shaftjournaled therein comprising a cylindrical drive element removably at-- tached to the driving shaft and rotatable therewith, a sleeve element slidable axially on said drive element for limited axial movement andconnected for rotationtherewith, means between" the drive element and the sleeve limiting the relative axial movement therebetween, means on one end of the sleeve removably receiving a drill chuck, projection cam means on the opposite end of said sleeve, shoulder means fixed non-rotatablv to the housing of the drill and having projection cam means in the path of the cam means on the sleeve, and means adjustably spacing the projection cam means on the sleeve with respect to the cam means on the shoulder.

2. A percussion attachment as claimed in claiml wherein the meansadjustably spacing the cam means one from the other is a screw threaded in the wall of the sleeve and having a conical tip engaging the end of the drive element. V i

3. A percussion. attachment as claimed in claim 1 wherein the means adjustably spacing the cam means,

one from the other, is the end on 'the drill'chuck ad justably positioned in said one end of, the sleeve and engaging the. end of the drive element to space the sleeve on the drive element.

4. A percussion. attachment as, claimed,- in, claim, 1 wherein the means between the drive element and the sleeve limiting the axially movement is an axial slot intermediate the ends of the, drive element receiving a pin through the wall of the sleeve.

5. A percussion attachment as claimed in claim 1 wherein the projection cam means on at least one of the sleeve and shoulder means are, in the form of partially recessed balls.

References Cited inthe file of this patent v TED ST TESPAT TS 1,040,424 Salt, -a Oct. 8, 1912 2,453,136 Karweit Nov. 9, 1948 2,458,929 Clark I Jan. 11, 1949 2,724,573 Lundquist Nov. 22, 1955 2,780,106 Lovequist Feb. 5, 1957 2 794 2 

